Concrete volute pump

Abstract

A centrifugal pump is provided capable of pumping liquid volume flow rates of at least 20 m3/sec. The pump includes a centrifugal impeller rotatable about an axis and operable to direct a liquid towards a concrete volute arranged around the impeller. The pump further includes fixed fin-like elements arranged between the impeller and the volute. The elements form a discontinuous barrier around the impeller and are effective to reduce uneven radial thrusts exerted by the water on the centrifugal impeller, while limiting the water flow rate in a simple and economic manner.

What is claimed is: 
     
       1. A concrete volute pump, comprising:
 a centrifugal impeller having blades, the impeller being arranged for rotation about an axis and operable to direct a liquid towards a concrete volute arranged around the impeller, wherein the pump further comprises fixed elements arranged between the impeller and the volute, said fixed elements comprising a discontinuous barrier around the impeller, 
 wherein for each fixed element, the difference between a radial distance from the rotational axis of the impeller to an end of the fixed element closest to the impeller, and the radial distance from the rotational axis of the impeller to an end of a blade furthest away from the axis of the impeller, represents from 1 to 10% of the radial distance from the rotational axis of the impeller to a periphery of the impeller, and 
 wherein, for each fixed element, the difference between the radial distance from the rotational axis of the impeller to a volute nozzle and the radial distance from the rotational axis of the impeller to an end of the fixed element furthest away from the rotational axis of impeller, represents from 3 to 10% of the radial distance from the rotational axis of the impeller to said end of the fixed element furthest away from the impeller. 
 
     
     
       2. The pump according to  claim 1 , wherein the pump is configured to pump liquid at volume flow rates of up to at least 40 m 3 /sec. 
     
     
       3. The pump according to  claim 1 , wherein said fixed elements comprise bodies each having a height dimension that extends generally spanwise across an outlet of the impeller, a width dimension that extends generally streamwise in a liquid flow and a thickness dimension that is smaller than the height and width dimensions. 
     
     
       4. The pump according to  claim 3 , wherein said fixed elements comprise streamwise curved partitions or fins. 
     
     
       5. The pump according to  claim 1 , wherein said fixed elements are substantially equally spaced around the impeller. 
     
     
       6. The pump according to  claim 1 , wherein said fixed elements are arranged substantially equidistantly from the rotational axis of the impeller. 
     
     
       7. The pump according to  claim 1 , wherein the number of impeller blades and the number of fixed elements are coprime. 
     
     
       8. The pump according to  claim 1 , wherein the volute is circular in cross-section. 
     
     
       9. The pump according to  claim 1  wherein the pump is configured to pump liquid at volume flow rates of up to at least 40 m 3 /sec. 
     
     
       10. The pump according to  claim 1 , wherein said fixed elements comprise bodies each having a height dimension that extends generally spanwise across an outlet of the impeller, a width dimension that extends generally streamwise in a liquid flow and a thickness dimension that is smaller than the height and width dimensions. 
     
     
       11. The pump according to  claim 1 , wherein the number of impeller blades and the number of fixed elements are coprime. 
     
     
       12. The pump according to  claim 1 , wherein the volute is circular in cross-section.